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From:   paulmck@kernel.org
To:     rcu@vger.kernel.org
Cc:     linux-kernel@vger.kernel.org, kernel-team@fb.com, mingo@kernel.org,
        jiangshanlai@gmail.com, dipankar@in.ibm.com,
        akpm@linux-foundation.org, mathieu.desnoyers@efficios.com,
        josh@joshtriplett.org, tglx@linutronix.de, peterz@infradead.org,
        rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com,
        fweisbec@gmail.com, oleg@redhat.com, joel@joelfernandes.org,
        "Paul E. McKenney" <paulmck@kernel.org>
Subject: [PATCH tip/core/rcu 07/26] rcu: Grace-period-kthread related sleeps to idle priority
Date:   Mon, 22 Jun 2020 17:21:28 -0700
Message-Id: <20200623002147.25750-7-paulmck@kernel.org>
In-Reply-To: <20200623002128.GA25456@paulmck-ThinkPad-P72>
References: <20200623002128.GA25456@paulmck-ThinkPad-P72>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

From: "Paul E. McKenney" <paulmck@kernel.org>

This commit converts the long-standing schedule_timeout_interruptible()
and schedule_timeout_uninterruptible() calls used by RCU's grace-period
kthread to schedule_timeout_idle().  This conversion avoids polluting
the load-average with RCU-related sleeping.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
 kernel/rcu/tree.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index db17ffe..48ae673 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -1620,7 +1620,7 @@ static void rcu_gp_slow(int delay)
 	if (delay > 0 &&
 	    !(rcu_seq_ctr(rcu_state.gp_seq) %
 	      (rcu_num_nodes * PER_RCU_NODE_PERIOD * delay)))
-		schedule_timeout_uninterruptible(delay);
+		schedule_timeout_idle(delay);
 }
 
 static unsigned long sleep_duration;
@@ -1643,7 +1643,7 @@ static void rcu_gp_torture_wait(void)
 	duration = xchg(&sleep_duration, 0UL);
 	if (duration > 0) {
 		pr_alert("%s: Waiting %lu jiffies\n", __func__, duration);
-		schedule_timeout_uninterruptible(duration);
+		schedule_timeout_idle(duration);
 		pr_alert("%s: Wait complete\n", __func__);
 	}
 }
@@ -2709,7 +2709,7 @@ static void rcu_cpu_kthread(unsigned int cpu)
 	}
 	*statusp = RCU_KTHREAD_YIELDING;
 	trace_rcu_utilization(TPS("Start CPU kthread@rcu_yield"));
-	schedule_timeout_interruptible(2);
+	schedule_timeout_idle(2);
 	trace_rcu_utilization(TPS("End CPU kthread@rcu_yield"));
 	*statusp = RCU_KTHREAD_WAITING;
 }
-- 
2.9.5